Heterogeneous Optical Space Switches for Scalable and Energy-Efficient Data Centers

Abstract

Optical space switches are key elements for the next generation of switching fabrics in backbone routers, high performance computing systems, and large data processing and storage systems. A number of architectures and alternative options for gating elements have been proposed, assessed, and implemented for a limited port count. The challenge is to further enhance the scalability and energy efficiency of space switches to support future traffic loads. This paper proposes a heterogeneous implementation of the space switches based on two different types of gating elements, namely semiconductor optical amplifiers (SOA) and Mach-Zehnder Interferometers (MZI). With respect to the existing homogeneous implementations, a higher energy efficiency can be achieved by minimizing the number of SOAs, but crosstalk is introduced by MZI. To reduce the power consumption while still guaranteeing adequate physical layer performance, the design of both Spanke and multi-stage architectures is optimized by strategically placing the different gating and amplification elements, and a physical layer analysis is carried out to validate the performance. The proposed heterogeneous implementation is able to achieve power savings up to 10% and 50% in the Spanke and multi-stage Beneš architectures, respectively, with respect to SOA-based space-switch implementations. Moreover, an improvement of the physical layer performance is achievable in the Spanke architecture thanks to the different placement of the SOAs.Index Terms-Energy efficiency, Mach-Zehnder interferometer (MZI), optical interconnection networks, power consumption, semiconductor optical amplifier (SOA), space switch.

Reliability Analysis of Multistage Interconnection Networks

“…The present work evaluated reliability calculations on various MINs . Although the approaches are applied to a realistic network such as computer communication networks, telecommunication networks, and transport networks, complex networks are used to interconnect multiple processing units in distributed systems.…”

“…Multiprocessor environment involves interconnecting a large number of processor or processor‐memory modules . It is a complicated task as it has to address issues such as connectivity, latency, bandwidth, cost, scalability, and reliability.…”

Reliable multistage interconnection network design

“…It interconnects N inputs with N outputs by connecting the processors to processors and/or to memory modules. MINs are fault tolerant, cost effective and provide low transmission delay using multistage switching fabrics routes to perform multiple communication tasks concurrently [16][17][18][19][20].…”

“…Benes Network [17] provide multiple paths at the initial stages but finally only one single path after the intermediate stages and behaves as less fault tolerant networks. Also, Clos network [10] is non-blocking MIN.…”

“…Two-Terminal and All-Terminal Reliability values of (RIN-1 and RIN-2) are found to be higher than all 4 disjoint MINs [10,19], 3 disjoint MINs (Enhanced IADM /3DGIN) and 2 disjoint MINs [11,12,17,18,22,23,26,27]. Terminal reliability of RIN-2 is equal to scalable crossbar network (SCN) [20] because in the SCN, there is only one switching element between each sourcedestination pair.…”